[PATCH v2] shell32/tests: Add test for IAutoComplete2 with custom source

[Marvin]

Hi,

While running your changed tests on Windows, I think I found new failures.
Being a bot and all I'm not very good at pattern recognition, so I might be
wrong, but could you please double-check?
Full results can be found at
https://testbot.winehq.org/JobDetails.pl?Key=34225

Your paranoid android.


=== w8 (32 bit autocomplete) ===
autocomplete.c:393: Test failed: Expected L"auto complete", got L"auto"

=== w864 (32 bit autocomplete) ===
autocomplete.c:393: Test failed: Expected L"auto complete", got L"auto"

=== w1064 (32 bit autocomplete) ===
autocomplete.c:393: Test failed: Expected L"auto complete", got L"auto"

=== w864 (64 bit autocomplete) ===
autocomplete.c:393: Test failed: Expected L"auto complete", got L"auto"